Benthic Diatoms in the Plankton of Admiralty Bay (Western Antarctic Peninsula): Taxonomy and Potential Implications to the Pelagic Community

In coastal regions of Antarctica, primary production is a result of the interaction between four communities: cryophilic microalgae, phytoplankton, microphytobenthos and macroalgae. Microphytobenthos can be equally important to eponthic microbiota, or even hold the bulk of primary production in periods a er the ice melting in late spring. Among the various groups forming the benthic community, diatoms are the most important photoautotrophs regarding diversity as well as the biomass available to the consumers. In this report we present a taxonomic survey of diatoms belonging to the Class Bacillariophyceae found in the plankton of Admiralty Bay, from samples collected between 2002 and 2010 in every December and February. A total of 53 species was recorded. e majority of the diatoms have benthic habit, usually associated to ice or rocks and macroalgae, indicating the in uence of bottom communities over the superjacent plankton. ose species were recorded in the water column possibly due to the local hydrographic dynamics, which might resuspend cells from microphytobenthos. Regarding taxonomy, about 25 species are newly reported to Admiralty Bay, and several identi cation and nomenclatural problems were found. We recommend that the ongoing monitoring program in the region includes sampling of the benthic community looking for di erent substrates like ice, rocks and macroalgae, also aiming to determine the origin of benthic diatoms found in the plankton of Admiralty Bay.